The purpose of this proposal is to pursue molecular and genetic analysis of acetylcholine synthesis and packaging in the soil nematode Caenorhabditis elegans. These studies focus on two genes and proteins: cha-1 is the structural gene for choline acetyltransferase (ChAT), the enzyme which synthesizes the neurotransmitter acetylcholine, and unc-17 is the gene which encodes the synaptic vesicle acetylcholine transporter (VAChT);cha-1 and unc-17 are tightly linked and define the "cholinergic gene locus". A similar genomic structure is present in all metazoans thus far examined, suggesting that functional constraints operate to maintain this type of genomic organization. C. elegans is being used for these studies because of its simple nervous system, its ease of genetic and molecular analysis, and the availability of convenient DNA-mediated transformation techniques. The specific aims include testing a model of cholinergic transcript alternative splicing, and identifying factors involved in the mechanism and the regulation of such splicing. The results of these studies will elucidate the mechanisms used within nerve terminals to coordinate neurotransmitter supply and demand. PUBLIC HEALTH RELEVANCE: Although the proposed studies are basic research, they are clearly relevant to health, since alterations in acetylcholine metabolism and/or cholinergic function have been identified in many neurological, neuromuscular, and psychiatric disorders, including congenital myasthenic syndromes, Alzheimer's disease, and depression.